Charged for 1 month, expired one day after.

You'll get charged when your subscription expires so if the last day of your current subscription is 4/1, you'd be charged either 4/1 or 4/2 (not 100% on the exact date but it will not be a month later).

You'll be sent an e-mail warning 30 days before your subscription expires explaining everything (and another one shortly before it will charge you).

The only thing with that is that they charged me the day i purchased my first 1 month. They charged me on the 20th of November when they should of charged me today when it expired.

Hello,

I'm not sure if the account you're logged into is the one that you're inquiring about, but this account seems to have a gold membership which doesn't look to be expired. If you're talking about another gamertag of a friend then I would suggest that you get
your friend to check his or her Xbox LIVE subscription history here. That page shows the type of subscription if any was on the account, the time it was started,
and the time it's due to cancel/renew.

If your friend doesn't see any history there then please have them contact phone support directly in regards to the issue they are experiencing with
having a 1 month gold membership expire within 1 day.

Wait till the ultimate expires then add it and upgrade

So after it expires I redeem the 3 months of gold and will it convert to 50 days and 1 month of ultimate at no cost?

Usually Xbox memberships charge you for the next month a few days before it expires, unless cancelled.